CN111098601B

CN111098601B - Recording control device, recording device, and recording control method

Info

Publication number: CN111098601B
Application number: CN201911012116.6A
Authority: CN
Inventors: 林拓马
Original assignee: Seiko Epson Corp
Current assignee: Seiko Epson Corp
Priority date: 2018-10-26
Filing date: 2019-10-23
Publication date: 2021-07-30
Anticipated expiration: 2039-10-23
Also published as: JP7147465B2; US10850543B2; CN111098601A; JP2020066197A; US20200130392A1

Abstract

The present invention provides a recording control device, a recording device and a recording control method. It is required to find a way to calculate a correction value for correcting uneven density. The recording control device of the present invention includes: a test pattern recording control unit for causing the recording device to record a test pattern including a plurality of ink recording areas with different ink amounts, and a correction value calculation unit for The correction value of the ink amount of each nozzle is calculated by reading the value; the correction recording control part makes the recording device record the image in which the ink amount of each nozzle is corrected by the correction value, and the medium of the recording medium on which the test pattern is recorded Compared with the case where the type is the first recording medium, when the medium type of the recording medium on which the test pattern is recorded is the second recording medium in which the ink bleeds more easily than the first recording medium, the correction value calculation unit calculates the correction value. The read value used in the calculation of the corresponding ink recording area corresponds to a smaller maximum ink volume.

Description

Recording control device, recording device, and recording control method

Technical Field

The invention relates to a recording control apparatus, a recording apparatus, and a recording control method.

Background

There is known a printing system that prints a correction pattern on a medium by an inkjet printer, sets a correction value for each raster line based on a read result of the correction pattern, and forms dots of the corresponding raster line so as to have a density corrected based on the correction value during a dot forming operation (see patent document 1).

Depending on the characteristics of the medium on which the correction pattern is printed, bleeding may occur in a high-density portion of the correction pattern. The correction pattern in which the ink is smeared has a problem that it is impossible to accurately read density unevenness caused by variations in ejection characteristics of each nozzle of the printer, and thus an appropriate correction value for correcting the density unevenness cannot be calculated.

Patent document 1: japanese patent laid-open publication No. 2005-205691

Disclosure of Invention

A recording control device for controlling a recording device that performs recording by ejecting ink from a plurality of nozzles, the recording control device comprising: a test pattern recording control unit that causes the recording device to record a test pattern including a plurality of ink recording regions having different ink amounts; a correction value calculation unit that calculates a correction value of the amount of ink for each of the nozzles based on a read value of the ink recording area of the test pattern to be recorded; and a correction recording control unit that causes the recording device to record an image in which the amount of ink for each of the nozzles is corrected by the correction value, wherein the correction value calculation unit is configured to calculate the correction value such that the maximum amount of ink in the ink recording region corresponding to the read value is smaller when the type of the recording medium on which the test pattern is recorded is a second recording medium that is more prone to ink bleeding than the first recording medium, than when the type of the recording medium on which the test pattern is recorded is the first recording medium.

Drawings

Fig. 1 is a diagram showing a schematic configuration of a system.

Fig. 2 is a diagram simply showing an example of the relationship between the recording head and the recording medium.

Fig. 3 is a diagram simply showing another example of the relationship between the recording head and the recording medium.

Fig. 4 is a flowchart showing a correction value acquisition process according to the first embodiment.

Fig. 5 is a diagram showing an example of a test pattern.

Fig. 6 is a graph showing read values of test patterns recorded on a recording medium.

Fig. 7 is a graph showing read values of test patterns for different media types.

Fig. 8 is a diagram for explaining an example of steps S130 and S140.

Fig. 9 is a diagram showing an example of the correction value table.

Fig. 10 is a flowchart showing a recording control process of an input image.

Fig. 11 is a flowchart showing details of step S220.

Fig. 12 is a flowchart showing a correction value acquisition process according to the second embodiment.

Fig. 13 is a diagram for explaining an example of steps S310 and S320.

Fig. 14 is a flowchart showing a correction value acquisition process including a specific example of step S300.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that each of the drawings is merely an example for explaining the present embodiment.

1. Brief description of the system:

fig. 1 simply shows the configuration of a system 1 according to the present embodiment. The system 1 includes a recording control apparatus 10 and a printer 20. The system 1 may also be referred to as a recording system, an image processing system, a printing system, or the like.

The recording control device 10 is realized by, for example, a personal computer, a smart phone, a tablet terminal, or an information processing device having a processing capability comparable to those of these devices. The recording control apparatus 10 includes a control unit 11, a display unit 13, an operation receiving unit 14, a communication interface 15, and the like. The interface is briefly labeled IF. The control unit 11 includes one or more ICs including a CPU11a, a ROM11b, a RAM11c, and the like as processors, and other nonvolatile memories.

In the controller 11, the CPU11a serving as a processor executes arithmetic processing in accordance with a program stored in the ROM11b or another memory, with the RAM11c or the like being a work area. The control unit 11 implements a plurality of functions of the TP recording control unit 12a, the correction value calculation unit 12b, the correction recording control unit 12c, the medium determination unit 12d, and the like in cooperation with the recording control program 12 by executing processing conforming to the recording control program 12, for example. The test pattern is briefly labeled TP. The processor is not limited to one CPU, and may be configured to execute processing by a plurality of CPUs, a hardware circuit such as an ASIC, or may be configured to execute processing in cooperation with the CPUs and the hardware circuit.

The display unit 13 is a unit for displaying visual information, and is configured by, for example, a liquid crystal display, an organic EL display, or the like. The display unit 13 may include a display and a driving circuit for driving the display. The operation receiving unit 14 is a means for receiving an operation performed by a user, and is implemented by, for example, a physical button, a touch panel, a mouse, a keyboard, or the like. Of course, the touch panel may be implemented as one function of the display unit 13. The display unit 13 and the operation receiving unit 14 may be referred to as an operation panel of the recording control apparatus 10.

The display unit 13 and the operation receiving unit 14 may be a part of the configuration of the recording control apparatus 10, but may be peripheral devices externally provided to the recording control apparatus 10. The communication IF15 is a generic term for one or more IFs used by the recording control apparatus 10 to perform communication with the outside by wire or wirelessly in accordance with a predetermined communication protocol including a known communication standard. The control section 11 communicates with the printer 20 via the communication IF 15.

The printer 20, which is a recording apparatus controlled by the recording control apparatus 10, is an ink jet printer that ejects dots of ink to perform recording. The dots are also referred to as droplets. Although a detailed description of the inkjet printer is omitted, the printer 20 is schematically provided with a transport mechanism 21, a recording head 22, and the like. The transport mechanism 21 transports the recording medium in a predetermined transport direction. As illustrated in fig. 2 and 3, the recording head 22 includes a plurality of nozzles 23 capable of ejecting dots, and dots are ejected from the nozzles 23 with respect to the recording medium 30 conveyed by the conveying mechanism 21. The printer 20 can eject dots or non-eject dots from the nozzles 23 by controlling application of a drive signal to a drive element, not shown, included in the nozzles 23 in accordance with dot data described later. The printer 20 performs printing by discharging ink of each color, for example, cyan (C), magenta (M), yellow (Y), and black (K), or ink or liquid other than the ink of each color. In the present embodiment, the printer 20 is described as a type that ejects CMYK inks.

Fig. 2 simply shows the relationship of the recording head 22 and the recording medium 30. The recording head 22 may also be referred to as a print head, a liquid discharge head, or the like. The recording medium 30 is typically paper, but may be any material other than paper as long as it is a material capable of performing recording by liquid ejection. The recording head 22 is mounted on a carriage 24 that is capable of reciprocating in a predetermined direction D1, and moves together with the carriage 24. The direction D1 is also referred to as the main scanning direction D1. The conveying mechanism 21 conveys the recording medium 30 in a direction D2 intersecting the direction D1. The direction D2 is the conveying direction. Although the intersections described here are substantially orthogonal, the directions D1 and D2 may not be strictly orthogonal due to various errors in the printer 20 as a product, for example. The conveying direction D2 is also referred to as a sub-scanning direction.

Reference numeral 25 denotes a nozzle surface 25 of the recording head 22, on which the nozzles 23 are opened. In fig. 2, one example of the arrangement of the nozzles 23 on the nozzle face 25 is shown. The recording head 22 includes a nozzle row 26 for each ink color in a configuration in which ink of each color of CMYK is supplied from an ink holding unit, not shown, called an ink cartridge or an ink tank, mounted on the printer 20 and discharged from the nozzles 23. The nozzle row 26 is configured by a plurality of nozzles 23, and the nozzle pitch, which is the interval between the nozzles along the direction D2, of the plurality of nozzles 23 is fixed. The recording head 22 includes four nozzle rows 26 corresponding to CMYK inks, for example. It goes without saying that the arrangement of the plurality of nozzles 23 constituting the nozzle row 26 corresponding to one color of ink does not need to be a single straight line as in fig. 2 and 3, and may be divided into a plurality of rows, for example.

According to the example of fig. 2, the printer 20 alternately repeats conveyance of a predetermined conveyance amount of the recording medium 30 by the conveyance mechanism 21 and ink ejection by the recording head 22 with movement of the carriage 24, thereby realizing recording on the recording medium 30. The ink ejection by the recording head 22 in accordance with the movement of the carriage 24 is also referred to as scanning or circulation. According to the example of fig. 2, the printer 20 is a serial printer which performs recording by the recording head 22 mounted on the carriage 24 which reciprocates in the direction D1 intersecting the direction D2.

However, the printer 20 may be a line printer in which the long recording head 22 records in a direction D1 intersecting the direction D2, as illustrated in fig. 3.

With regard to fig. 3, the difference from fig. 2 will be explained simply. According to the example of fig. 3, the nozzle row 26 in the nozzle face 25 is constituted by a plurality of nozzles 23 whose nozzle pitch along the direction D1 is set to be fixed. The nozzle row 26 has a length that extends over a range corresponding to the width of the recording medium 30 in the direction D1, and the recording head 22 having a plurality of such nozzle rows 26 according to the ink color is not mounted on the carriage but fixed. Further, according to the example of fig. 3, in the printer 20, ink ejection by the recording head 22 is performed with respect to the recording medium 30 being conveyed at a predetermined speed by the conveying mechanism 21.

The recording control unit 10 is further connected to the color measuring device 40 so as to be able to communicate with each other. The color measuring device 40 is a generic term for a device for measuring color of the recording medium 30. The color measuring device 40 is, for example, a dedicated color meter or a scanner that optically reads an object and generates image data. The color measuring device 40 may be a part of the recording control device 10.

The recording control apparatus 10 and the printer 20 may be connected via a network not shown. The printer 20 may be a multifunction peripheral having a plurality of functions such as a scanner function and a facsimile communication function in addition to a printing function. The recording control apparatus 10 may be realized not only by a single independent information processing apparatus but also by a plurality of information processing apparatuses communicably connected to each other via a network.

Alternatively, the recording control apparatus 10 and the printer 20 may be integrated. That is, the recording control apparatus 10 is a part of the configuration included in the printer 20 as the recording apparatus, and the processing executed by the recording control apparatus 10 described below can be understood as the processing executed by the printer 20.

2. The first embodiment:

fig. 4 shows a flowchart of the correction value acquisition process according to the first embodiment, which is realized by the control unit 11 according to the recording control program 12. In the present embodiment, at least a part of each step shown in the flowchart shows each step of the recording control method. The correction value is information for suppressing density unevenness caused by variations in ejection characteristics of each nozzle 23 of the printer 20.

In step S100, the TP recording control unit 12a causes the printer 20 to record TPs including a plurality of density regions having different amounts of ink. The density region is a region to be recorded by the ink, and is therefore also referred to as an "ink recording region". TP data, which is image data representing TPs, is prepared in advance in a predetermined memory or the like. The TP data is bitmap data having gradation values (for example, 256 gradations of 0 to 255) each pixel represents the ink amount of each CMYK. The TP recording control unit 12a performs halftone processing on the TP data. The specific method of the halftone processing is not particularly limited, and a dither method, an error diffusion method, or the like can be used. Dot data in which dots of each of CMYK inks are ejected (dot on) or not ejected (dot off) is generated by halftone processing.

The TP recording control unit 12a sorts the generated dot data information in the order in which they should be transferred to the printer 20 according to a predetermined recording method. This ordered process is also referred to as a rasterization process. The recording method used here is a recording method adopted by the printer 20 for the movement of the transport mechanism 21 and the recording head 22. If the recording method is different, the amount of conveyance by the conveyance mechanism 21 once between cycles, the number of cycles necessary for recording on one recording medium 30, and the like will be different. Therefore, the rasterization process determines which nozzle 23 ejects the ink dot specified by the dot data at which timing according to the pixel position and the ink color. The TP recording control unit 12a transmits the rasterized dot data to the printer 20. Thereby, the printer 20 executes recording of the TP to the recording medium 30 based on the dot data transmitted from the recording control apparatus 10.

Fig. 5 illustrates TP50 recorded on the recording medium 30 in step S100. In TP50, a plurality of elongated ink recording regions a1, a2, A3, a4, a5, a6, a7, A8, a9, and a10 are arranged in the short side direction of each ink recording region. In the ink recording regions a1 to a10 included in TP50, the amounts of ink were different from each other, and recording was performed with the same one color ink. In TP50 shown in fig. 5, all of the ink recording regions a1 to a10 were recorded with K ink. In fig. 5, for easy understanding, the ink amounts in the ink recording regions a1 to a10 are converted to values (Duty) in a numerical range of 10% minimum value to 100% maximum value, and are illustrated with parentheses. That is, the ink amount may be referred to as Duty. The ink recording region a1 having the smallest ink amount is Duty 10%, and the duties of the other ink recording regions a2 to a10 having a larger ink amount than the ink recording region a1 are increased at intervals of 10%.

The Duty of the ink recording area refers to the ratio of pixels in which dots in the area are on, or the coverage of the area with ink. In the TP data representing TP50, each of the ink recording regions a1 to a10 is a set of pixels having gradation values corresponding to the respective duties. The value range of 0% to 100% can be normalized within the gray scale range of 0 to 255. Therefore, in the TP data expressing TP50, the ink recording region a1 is formed as a pixel having a tone value "26" of K corresponding to Duty 10%, that is, a pixel set having (C, M, Y, K) ═ 0, and 26, for example. In addition, in the TP data expressing TP50, the ink recording region a10 is formed as a pixel set having a tone value "255" of K corresponding to Duty 100%, that is, (C, M, Y, K) pixels of (0, 255), for example.

The TP recording controller 12a causes the printer 20 to record TP50 in a direction in which the nozzles 23 of the nozzle row 26 corresponding to the K ink of the recording head 22 record ink recording regions a1, a2, A3, a4, a5, a6, a7, A8, a9, and a 10. If the printer 20 is a serial printer as described with reference to fig. 2, the TP recording control unit 12a records TP50 on the recording medium 30 in a direction in which the short side direction of each ink recording region corresponds to the direction D1 and the long side direction of each ink recording region corresponds to the direction D2. On the other hand, if the printer 20 is a line printer as described with reference to fig. 3, the TP recording control unit 12a records TP50 on the recording medium 30 in a direction in which the short side direction of each ink recording region corresponds to the direction D2 and the long side direction of each ink recording region corresponds to the direction D1.

In fig. 5, the area indicated by the dotted line illustrates the grating line RL. The raster line RL is a region in which pixels recorded by one nozzle 23 that ejects K ink are arranged in a fixed direction, and is a part of an image. That is, in step S100, the TP recording control unit 12a performs recording of one raster line RL for each nozzle 23 whose position in the longitudinal direction of the nozzle row 26 is different, thereby recording TP50 as a bundle of raster lines RL.

In step S110, the correction value calculation unit 12b acquires the read value of TP recorded in step S100. In this case, the color measuring device 40 measures the color of TP recorded on the recording medium 30, and the correction value calculating unit 12b obtains the read value as the color measurement result from the color measuring device 40. The color system used for the read value acquired by the correction value calculation unit 12b is not particularly limited. The correction value calculation unit 12b obtains, as read values, color values expressed by L, a, and b components in the CIE L × a × b color space defined by the international commission on illumination (CIE), or obtains, as read values, image data expressed by RGB (red, green, and blue) components from the color measuring device 40 serving as a scanner.

In step S120, the correction value calculation unit 12b determines the type of the recording medium 30 on which the TP is recorded in step S100, that is, the medium type, based on the read value acquired in step S110. In the present embodiment, the meaning of the medium type is different depending on the ease of ink bleeding.

For example, when the bleeding ease of ink is compared with respect to special paper for inkjet printing, plain paper, and recycled paper, the ink for special paper is most difficult to bleed, and the ink for recycled paper is most likely to bleed. In this embodiment, when one of different media types is referred to as a first recording medium, a media type in which ink is more likely to bleed than the first recording medium is referred to as a second recording medium. For example, when the special paper is understood as the first recording medium, plain paper or recycled paper corresponds to the second recording medium. For example, when plain paper is understood as the first recording medium, the reproduced paper corresponds to the second recording medium. The ink is likely to bleed, which means that the ink is likely to permeate the medium and the dots of the ink are likely to be mixed with each other.

Fig. 6 shows the read values obtained in step S110 by a graph. In fig. 6, the abscissa represents Duty of the ink recording regions a1 to a10 of TP50, and the ordinate represents luminance as a read value. The luminance as the read value is the luminance L input from the colorimeter device 40. Alternatively, the luminance as the read value may be a value calculated by the control unit 11 based on information input from the color measuring device 40, for example, a value obtained by adding RGB components by weighting.

In the graph of fig. 6, 10 black dots equally spaced in the horizontal axis indicate the brightness of each of the ink recording regions a1 to a10 of TP 50. The respective luminances of each ink recording region indicated by these black dots are, for example, average values of the luminances of each ink recording region in the raster lines RL recorded by one nozzle 23 of the nozzle row 26 corresponding to the K ink of the recording head 22. Alternatively, the respective luminances of the ink recording regions indicated by the black dots are, for example, average values of the luminances of the ink recording regions of the respective raster lines RL recorded by the nozzles 23 of the nozzle row 26 of the recording head 22 corresponding to the K ink. The curve connecting these black dots is a function generated by the correction value calculation unit 12b by interpolation of the brightness of the ink recording regions a1 to a 10. Of course, the interpolation operation may be linear interpolation. As can be seen from fig. 6, the brightness of the ink recording areas a1 to a10 decreases as the Duty of the ink recording areas increases.

Fig. 7 shows, by a graph, in the same manner as fig. 6, the read values of TP50 for each recording medium 30 in the case where the printer 20 has recorded TP50 on each of the recording media 30 of different media types. Specifically, the function indicated by the broken line in fig. 7 indicates the read value of TP50 recorded by the printer 20 for the recording medium 30 as the reproduction paper. In fig. 7, a function indicated by a two-dot chain line shows a read value of TP50 recorded by the printer 20 for the recording medium 30 as plain paper. In fig. 7, a function indicated by a solid line shows a read value of TP50 recorded by the printer 20 for the recording medium 30 which is the special paper.

In the media types where the ink is liable to bleed, in particular, in the high Duty region where the ink is recorded in large quantities, the change in color is lacking. According to the example of fig. 7, the decrease rate of the luminance of TP50 recorded on the reproduction paper with respect to the increase in Duty becomes smaller from the vicinity where Duty on the horizontal axis exceeds 50% of the center. On the other hand, in the medium type in which the ink hardly blurring, the color largely changes even in the high Duty region. According to the example of fig. 7, even after the Duty of the horizontal axis exceeds 50% of the center, the luminance of TP50 recorded on the special paper is greatly reduced as compared with the recycled paper or the plain paper.

Therefore, in step S120, the correction value calculation unit 12b determines the type of medium on the recording medium 30 on which the TP is recorded in step S100, based on the read value corresponding to the high Duty region among the read values acquired in step S110. For example, the correction value calculation unit 12b compares the brightness of the read value of the ink recording area a10 corresponding to Duty 100% among the read values obtained in step S110 with the preset thresholds TH1 and TH 2. TH1 > TH 2. The threshold TH1 is a value for identifying the brightness of the ink recording area a10 on the recycled paper and the brightness of the ink recording area a10 on the plain paper. The threshold TH2 is a threshold for identifying the brightness of the ink recording area a10 on plain paper and the brightness of the ink recording area a10 on special paper. If the brightness of the ink recording area A10 is higher than the threshold TH1, the correction value calculation section 12b determines that the medium type is "recycled paper". If the brightness of the ink recording area a10 is equal to or less than the threshold TH1 and is higher than the threshold TH2, the correction value calculation unit 12b determines that the medium type is "plain paper". If the brightness of the ink recording area A10 is equal to or less than the threshold TH2, the correction value calculation unit 12b determines that the medium type is "special paper".

Alternatively, the correction value calculation unit 12b may determine the type of medium based on the difference in read values between a plurality of ink recording regions corresponding to the high Duty region. For example, the correction value calculation section 12b calculates the difference (luminance difference) between the luminance of the ink recording region a7 corresponding to Duty 70% and the luminance of the ink recording region a10 corresponding to Duty 100% among the read values obtained in step S110. Then, the correction value calculation unit 12b determines the type of the medium by, for example, comparing the luminance difference with a predetermined threshold value. Since the luminance difference tends to be a smaller value as the type of the medium in which the ink is likely to bleed is larger, the correction value calculation unit 12b can determine the type of the medium 30 on which the TP is recorded in step S100, from the luminance difference.

In step S130, the correction value calculation unit 12b determines the ink amount range of TP to be referred to for correction value calculation, based on the type of medium determined in step S120. The meaning of reference for the correction value calculation means that the read value is used for the correction value calculation. In the first embodiment, if the minimum ink amount in the ink amount range of TP to be referred to for correction value calculation is the lowest Duty in TP, that is, TP50 in fig. 5, the Duty of the ink recording area a1 is determined to be 10%. Therefore, step S130 is a process of substantially determining the maximum amount of ink of TP to be referred to for correction value calculation.

Fig. 8 is a diagram for explaining an example of steps S130 and S140.

In the upper part of fig. 8, an ink amount range table 16 which specifies the correspondence between the medium type and the ink amount range of TP is shown. The ink amount range table 16 is stored in advance in a predetermined memory in the recording control apparatus 10, for example. The correction value calculation unit 12b determines the ink amount range of TP to be referred to for correction value calculation, based on the medium type determined in step S120 and the ink amount range table 16. In the ink amount range table 16 of fig. 8, the ink amount is shown by Duty. According to the ink amount range table 16, if the medium type is special paper, the correction value calculation section 12b determines the ink amount range to be Duty 10% to 100%, if the medium type is plain paper, the ink amount range to be Duty 10% to 70%, and if the medium type is recycled paper, the ink amount range to be Duty 10% to 50%. The maximum ink amount (maximum Duty) in the ink amount range for each media type defined in the ink amount range table 16 is a value that decreases as the corresponding media type is a media type in which bleeding is likely to occur. The highest Duty of the ink amount range for each media type specified in the ink amount range table 16 is the upper limit of the Duty that is considered as the non-bleeding ink in the corresponding media type.

In this way, in step S130, the correction value calculation unit 12b sets the maximum ink amount in the ink recording region of the TP to be referred to for the correction value calculation to a smaller value as the recording medium 30 on which the TPs are recorded by the printer 20 in step S100 is the medium type in which the ink is more likely to bleed. This is because the density unevenness corresponding to the variation in the ejection characteristics of each nozzle 23 that should originally be present is not correctly represented in the read value obtained by reading the recorded result of the state in which the ink has run. Even if a read value, which does not accurately represent the density unevenness as a result of color measurement of TP, is used for calculation of the correction value, an appropriate correction value for correcting the density unevenness cannot be obtained.

In step S140, the correction value calculation unit 12b calculates a correction value for correcting the ink amount for each nozzle 23 based on the read value of the ink recording area in the ink amount range determined in step S130, from the read values of TP obtained in step S110. Fig. 8 illustrates an example in which the ink amount range is determined to be Duty 10% to 70% in step S130, and as a result, the ink amount range corresponding to the read value used for the calculation of the correction value in step S140 is limited to Duty 10% to 70%.

In the lower part of fig. 8, the read value acquired in step S110 is shown by a graph. The graph looks the same as in fig. 6 and 7. In the graph of fig. 8, 7 black dots equally spaced in the horizontal axis direction indicate the brightness of each of the ink recording regions a1 to a7 of TP 50. In the graph of fig. 8, the brightness of each ink recording region indicated by the black dots is an average value of the brightness of each ink recording region in the raster lines RL recorded by one nozzle 23 of the nozzle row 26 corresponding to the K ink of the recording head 22. For convenience of explanation of step S140, the one nozzle 23 is referred to as a "target nozzle". The solid line connecting the 7 black dots in the graph of fig. 8 is a function F1 generated by interpolation, and the target nozzle can be said to represent the change in the brightness reproduced on the recording medium 30 so as to correspond to the Duty 0% to 70% of the K ink. The correction value calculation unit 12b calculates a correction value for the target nozzle.

In the present embodiment, it is assumed that the nozzle row 26 corresponding to one ink color in the recording head 22 includes N nozzles 23 along the longitudinal direction of the nozzle row 26. For convenience of explanation, the nozzle numbers N (N is 1 to N) are assigned to the N nozzles 23 in order from one end side to the other end side in the longitudinal direction of the nozzle row 26. The correction value calculation unit 12b determines which raster line RL is the read value of the recording result of which nozzle 23 by associating the read value of each raster line RL included in the read value of TP acquired in step S110 with the nozzle number n.

In the graph of fig. 8, the function TG indicated by a one-dot chain line is a curve generated by interpolating the respective luminances of the respective ink recording regions in the raster line RL recorded by the target nozzle. The target nozzle is also one of the nozzles 23 included in the nozzle row 26 corresponding to the K ink of the recording head 22. The correction value calculation unit 12b specifies, as a target nozzle, the nozzle 23 having the brightest read value among the nozzles 23 included in the nozzle row 26 corresponding to the K ink, for example, based on the read value of TP50 acquired in step S110. As in the example of fig. 8, when the highest Duty of the ink amount range of TP50 to be referred to for the correction value calculation is 70%, the correction value calculation section 12b specifies the nozzle 23 having the highest reading value (brightness) of the ink recording area a7 corresponding to Duty 70% as the target nozzle. The target nozzle is a reference for correction of the target nozzle.

As illustrated in the graph of fig. 8, the luminance indicated by the function F1 corresponds to the Duty 70% and is the luminance v1, and the luminance indicated by the function TG corresponds to the same Duty 70% and is the luminance v 2. In this case, the correction value calculation unit 12b sets the Duty for obtaining the luminance v2 in the function F1 to the Duty after correction of Duty 70%. If the gradation value in the 256 gradation range corresponding to Duty 70% is "k 1" and the gradation value in the 256 gradation range corresponding to Duty 70% after the correction is "k 1 '", the correction value calculation unit 12b sets k 1' -k1 as a correction value with respect to the gradation value k 1. For example, if k1 ═ 170 and k1 ═ 165, then "-5" becomes a correction value for the gradation value k 1. The correction value calculation unit 12b calculates a correction value for all the gradations 0 to k1 of the gradation value k1 or less by using the function F1 and the function TG.

The correction value calculation unit 12b may calculate a correction value for a tone value outside the range of the functions F1 and TG by copying the already calculated correction value, linear interpolation, or the like. In the example of fig. 8, the correction value calculation unit 12b may copy the correction value for the tone value k1 as the correction value for each of the tone values k1+1 to 255.

The correction value calculation unit 12b calculates correction values for all the gradation values with respect to the 256 gradation ranges for the nozzles 23 other than the target nozzles among the nozzles 23 included in the nozzle row 26 corresponding to the K ink by sequentially setting the nozzles 23 other than the target nozzles among the nozzles 23 included in the nozzle row 26 corresponding to the K ink as the target nozzles.

In step S150, the correction value calculation unit 12b stores the correction value calculated in step S140 in the above manner in a predetermined memory in the recording control device 10.

It is needless to say that the control section 11 defines the target nozzles and the target nozzles for each nozzle row 26 corresponding to CMY inks other than the K ink, and calculates and stores the correction values for each target nozzle in the above manner. That is, with the control section 11, in step S100, not only the printer 20 is caused to execute recording of TPs by K ink but also the printer 20 is caused to execute recording of TPs by each of CMY inks, and the steps below step S110 are executed in the same manner. However, the processing in steps S120 and S130 may be executed based on the read value of TP recorded with ink of any one of CMYK colors.

Fig. 9 illustrates the result of step S150, that is, the correction value table 17 stored in the recording control apparatus 10. The correction value table 17 stores the correction values calculated in step S140, that is, the correction values of CMYK for each ink color and each nozzle number N (N is 1 to N). The "correction values 0 to 255" in fig. 9 are expressions summarizing the existence of the correction values for the respective tone values of 0 to 255. However, regarding each of CMYK, a correction value is not stored for the nozzle number N corresponding to the target nozzle among the nozzle numbers 1 to N.

Fig. 10 shows a recording control process of causing the printer 20 to execute recording of an input image arbitrarily selected by a flowchart. The recording control process is also realized by the control unit 11 according to the recording control program 12. The recording control process is accompanied by a correction process using the correction value calculated in the above-described manner.

The user can arbitrarily select image data representing an input image by operating the operation accepting section 14 while visually checking a user interface screen displayed on the display section 13, for example. The user interface is simply referred to as UI. In step S200, the correction recording control unit 12c acquires image data arbitrarily selected by the user from a predetermined input source.

The image data acquired in step S200 is bitmap data having a plurality of pixels, for example, RGB gradation values (for example, 256 gradation values of 0 to 255) for each pixel, as in the TP data. When the acquired image data does not correspond to such an RGB color system, the correction/recording control unit 12c converts the acquired image data into data of the color system. Further, the correction/recording control unit 12c appropriately performs resolution conversion processing and the like for the image data in accordance with the print resolution adopted by the printer 20.

In step S210, the correction/recording control unit 12c performs a color conversion process on the image data obtained in step S200. That is, the color system of the image data is converted into the color system of the ink used by the printer 20 in recording. As described above, when image data is expressed in gradation of colors of pixels by RGB, gradation values of RGB are converted into gradation values of CMYK for each pixel. The color conversion process can be executed by referring to an arbitrary color conversion look-up table that defines a conversion relationship from RGB to CMYK.

In step S220, the correction recording control unit 12c corrects the image data after the color conversion obtained in step S210 using the correction value stored in the correction value table 17.

Fig. 11 is a flowchart showing the details of the correction processing in step S220.

In step S221, the correction recording control unit 12c selects one pixel to be corrected from among a plurality of pixels constituting the image data.

In step S222, the correction recording control unit 12c selects a gradation value of one ink color to be corrected from the gradation values of each CMYK of the pixel selected in step S221.

In step S223, the correction recording control unit 12c reads the nozzle 23 to which the pixel selected in step S221 is assigned and the correction value corresponding to the ink color selected in step S222 from the correction value table 17, and corrects the gradation value of the ink color selected in step S222 based on the read correction value. The correction recording control unit 12c specifies to which nozzle 23 a pixel constituting the image data is assigned, according to the recording method adopted by the printer 20. For example, in step S221, a pixel corresponding to the nozzle number n of 10 is selected, and in step S222, a tone value of K ink, for example, a tone value of 50, which the pixel has, is selected. In this case, in step S223, the correction recording control unit 12c reads a correction value for correction having a gradation value of 50 corresponding to the K ink and the nozzle number n of 10 from the correction value table 17.

In step S224, the correction recording control unit 12c determines whether or not the correction in step S223 has been completed with respect to the gradation values of all the ink colors CMYK of the pixel selected in step S221, and returns to step S222 to reselect the gradation value for the ink color not subjected to correction when there is an ink color for which the correction has not been completed. On the other hand, when the correction in step S223 is completed for the gradation values of all the ink colors CMYK, the process proceeds to step S225.

In step S225, the correction recording control unit 12c determines whether or not the correction has been completed for all pixels constituting the image data, and if there is a pixel for which the correction has not been completed, the process returns to step S221 to newly select the pixel for which the correction has not been completed. On the other hand, when the correction of all the pixels is finished, the correction processing in step S220 is finished.

In step S230, the correction recording control unit 12c performs halftone processing on the image data after the correction processing performed in step S220, and generates dot data.

In step S240, the corrected record control unit 12c executes output processing for causing the printer 20 to execute recording based on the dot data generated in step S230. That is, the correction recording control unit 12c applies rasterization processing to the dot data and transmits the rasterized dot data to the printer 20. As a result, the printer 20 executes recording of the input image on the recording medium 30 based on the dot data transmitted from the recording control apparatus 10.

In the explanation of the flowchart of fig. 10, the correction value is to be corrected by the gradation value for each ink color included in the image data after the color conversion processing in step S210. However, the correction value is not limited to such a gradation value. For example, the color conversion look-up table to be referred to in the color conversion process may be corrected. That is, the correction recording control unit 12c may correct the CMYK values after the color conversion defined in the color conversion look-up table by the correction value for each color and for each tone value. The correction recording control unit 12c may increase or decrease the gradation value for each RGB that each pixel of the image data before the color conversion process has, based on the correction value. In this case, although the correction value thus calculated cannot be applied to RGB as it is, RGB can be indirectly corrected by the correction value by using a predetermined coefficient or a calculation formula in accordance with the relationship between the increase and decrease in RGB and the increase and decrease in CMYK in accordance with the increase and decrease in RGB.

3. Second embodiment:

fig. 12 is a flowchart showing the correction value acquisition process according to the second embodiment, which is realized by the control unit 11 in accordance with the recording control program 12. The second embodiment basically omits the description overlapping with the first embodiment. In the correction value acquisition process according to the first embodiment, the ink amount range of the TP to be referred to for correction value calculation is determined based on the read value of the TP recorded by the printer 20. In contrast, in the correction value acquisition process according to the second embodiment, the ink amount range to be referred to for the correction value calculation is determined prior to recording of TPs, and the printer 20 is caused to execute recording of TPs in the determined ink amount range.

In step S300, the medium determination unit 12d determines the medium type of the recording medium 30 used for recording the TP. For example, the medium determination unit 12d causes the display unit 13 to display a UI screen for inputting the type of medium. The user inputs the recording medium 30 used for recording the TP, that is, the type of the medium set in the printer 20, on the UI screen by operating the operation accepting unit 14. In this way, the medium determination unit 12d can determine what the medium type is by receiving the designation of the medium type from the user through the UI screen.

In step S310, the TP recording control unit 12a determines TP of the ink amount range corresponding to the medium type determined in step S300.

Fig. 13 is a diagram for explaining an example of steps S310 and S320. Fig. 13 shows an upper part of an ink amount range table 18 defining a correspondence relationship between the type of medium and the ink amount range of TP. The ink amount range table 18 is stored in advance in a predetermined memory in the recording control apparatus 10, for example. The TP recording control unit 12a determines the TP to be recorded by the printer 20 based on the medium type and the ink amount range table 18 determined in step S300. The maximum Duty (ink amount in the ink recording area AA 4) for each media type specified in the ink amount range table 18 is a lower value as the corresponding media type is a media type in which bleeding is more likely. The highest Duty of each medium type specified in the ink amount range table 18 is an upper limit of the Duty at which the ink is considered not to bleed in the corresponding medium type.

In step S320, the TP recording control unit 12a causes the printer 20 to record the TP determined in step S310. In the second embodiment, TP is an image including a plurality of ink recording regions having different ink amounts. According to the example of fig. 13, in the case where the medium type is determined to be the exclusive paper in step S300, the TP recording control portion 12a causes the printer 20 to record TP60 including the Duty 25% ink recording area AA1, the Duty 50% ink recording area AA2, the Duty 75% ink recording area AA3, and the Duty 100% ink recording area AA 4. Further, according to the example of fig. 13, in the case where the medium type is determined to be plain paper in step S300, the TP recording control portion 12a causes the printer 20 to record TP61 including the Duty 18% ink recording area AA1, the Duty 35% ink recording area AA2, the Duty 53% ink recording area AA3, and the Duty 70% ink recording area AA 4. Further, according to the example of fig. 13, in the case where the medium type is determined to be recycled paper in step S300, the TP recording control section 12a causes the printer 20 to record TP62 including the Duty 13% ink recording area AA1, the Duty 25% ink recording area AA2, the Duty 38% ink recording area AA3, and the Duty 50% ink recording area AA 4.

According to the example of fig. 13, the

TPs

60, 61, and 62 are images each configured such that a plurality of elongated ink recording regions AA1, AA2, AA3, and AA4 are aligned in the short side direction of each ink recording region. Like TP50 shown in fig. 5, the ink recording regions of TP60, 61, and 62 were recorded with the same ink of one color. If the printer 20 is a serial printer as described in fig. 2, the TP recording control unit 12a records any one of the

TPs

60, 61, and 62 on the recording medium 30 in a direction in which the short side direction of each ink recording region corresponds to the direction D1 and the long side direction of each ink recording region corresponds to the direction D2. On the other hand, if the printer 20 is a line printer as described in fig. 3, the TP recording control unit 12a records any one of the

TPs

60, 61, and 62 on the recording medium 30 in a direction in which the short side direction of each ink recording region corresponds to the direction D2 and the long side direction of each ink recording region corresponds to the direction D1.

For example, TP data, which is image data representing TP60, is prepared in advance in a predetermined memory or the like. When the TP recording control unit 12a causes the printer 20 to record TP60, it is only necessary to execute recording by the printer 20 so as to execute halftone processing or the like on TP data representing TP 60. On the other hand, when the printer 20 records TP61, the TP recording controller 12a performs correction of the respective ink amounts in the ink recording areas AA1, AA2, AA3, and AA4 to TP data representing TP60, which is defined in the ink amount range table 18 corresponding to plain paper, and converts the data into TP data representing TP 61. When the printer 20 is caused to record TP62, the TP recording control unit 12a performs correction of the respective ink amounts in the ink recording areas AA1, AA2, AA3, and AA4 to the TP data representing TP60, the respective ink amounts being defined in the ink amount range table 18 in accordance with the reproduced paper, and converts the data into TP data representing TP 62. When the printer 20 records TP61 or TP62, the TP recording control unit 12a may execute recording by the printer 20 by executing halftone processing or the like with respect to the TP data representing TP61 or TP data representing TP62 converted in the above-described manner.

In this way, in a configuration in which one of the

different TPs

60, 61, 62 is recorded according to the type of the recording medium 30 used for recording TPs, TP data representing one TP60 is converted into TP data representing the other TP61 or TP 62. This saves memory resources for storing TP data in advance.

In step S330, the correction value calculation unit 12b acquires the read value of TP recorded in step S320.

In step S340, the correction value calculation unit 12b calculates a correction value for correcting the ink amount for each nozzle 23 based on the read value of TP acquired in step S330. The method of calculating the correction value will be described in the first embodiment. However, in step S340, the correction value calculation unit 12b may calculate the correction value using the entire read values of the TPs acquired in step S330, that is, the read values of the TPs recorded on the recording medium 30 from the lowest Duty to the highest Duty in step S320.

Step S350 is the same as step S150.

Fig. 14 is a flowchart showing the correction value acquisition processing of the second embodiment, and shows a specific example of step S300 in detail by dividing into steps S302 to S306. Steps from step S310 to step S310 in fig. 14 are the same as those from step S310 to step S12 in fig. 12.

In step S302, the TP recording control unit 12a causes the printer 20 to record a predetermined pre-test pattern (hereinafter, pre-TP). The pre-TP is a TP for determining the type of medium, and is not a TP for obtaining a read value used for calculating the correction value. Therefore, the TP recording control unit 12a records the pre-TP on the recording medium 30 by using only a part of the nozzles 23 included in the recording head 22, for example, a part of the nozzles 23 included in one nozzle row 26. Note that the pre-TP may be any TP suitable for discriminating the type of medium. The pre-TP is, for example, a TP composed of the high Duty side ink recording regions a7, a8, a9, and a10 in TP50 shown in fig. 5.

In step S304, the medium determination unit 12d obtains the read value of the pre-TP recorded in step S302. That is, the color measuring device 40 measures the color of the pre-TP recorded on the recording medium 30, and the medium determining unit 12d obtains the read value as the result of the color measurement from the color measuring device 40.

In step S306, the medium determination unit 12d determines the medium type of the recording medium 30 based on the read value of the pre-TP acquired in step S304. The determination method in step S306 may be performed along the determination method in step S120 described in the first embodiment.

In this way, in step S300 of the second embodiment, the medium determination unit 12d may determine the medium type based on the read value of the pre-TP recorded on the recording medium 30, instead of determining the medium type based on an input from the user.

4. To summarize:

as described above, according to the present embodiment, the recording control apparatus 10 that controls the printer 20 that performs recording by ejecting ink from the plurality of nozzles 23 includes: a TP recording control unit 12a that causes the printer 20 to record TPs including a plurality of ink recording regions having different ink amounts; a correction value calculation unit 12b that calculates a correction value of the amount of ink for each nozzle 23 based on the read value of the ink recording area of the TP to be recorded; and a correction recording control unit 12c for causing the printer 20 to record an image in which the amount of ink for each nozzle 23 is corrected by the correction value. In addition, when the type of the recording medium 30 on which the TP is recorded is the second recording medium, on which ink is more likely to bleed than the first recording medium, the correction value calculation unit 12b calculates the correction value using a smaller maximum amount of ink in the ink recording region corresponding to the read value than in the case where the type of the recording medium 30 on which the TP is recorded is the first recording medium.

With such a configuration, when the recording control device 10 generates the correction value based on the read value of the TP recorded on the recording medium 30, the correction value can be generated by excluding the read value of the ink recording region in which the ink has entered a bleed state regardless of the type of the recording medium 30 used for recording the TP. Therefore, an appropriate correction value for correcting density unevenness due to variation in the ejection characteristics of the ink from each nozzle 23 can be generated.

According to the present embodiment, the correction value is generated based on the read value of the ink recording region in the state where the ink does not bleed on the recording medium 30, that is, the read value in which the variation in the ink ejection characteristics of the respective nozzles 23 is faithfully expressed as the recording result of the depth. Therefore, it can be said that such a correction value is an appropriate value for the correction process (step S220 in fig. 10) not only when the input image is recorded on the same type of recording medium 30 as the recording medium 30 used for the recording of the TP but also when the input image is recorded on a different type of recording medium 30 from the recording medium 30 used for the recording of the TP. In this way, the present embodiment can obtain a correction value suitable for correction processing in each case of performing recording on each type of recording medium 30, based on the read value of the TP recorded on one type of recording medium 30.

Further, according to the first embodiment, the correction value calculation unit 12b determines the medium type of the recording medium 30 on which the TP is recorded based on the read value of the TP recorded on the recording medium 30, and determines the maximum ink amount based on the determination result.

According to the above configuration, in the recording control apparatus 10, since the medium type is determined based on the read value of the TP recorded on the recording medium 30, the medium type of the recording medium 30 used for recording the TP can be accurately determined. As a result, the maximum ink amount in the ink recording area corresponding to the read value to be used for the correction value calculation can be appropriately determined according to the type of medium.

In addition, according to the second embodiment, the recording control device 10 includes the medium determination unit 12d, and the medium determination unit 12d determines the medium type of the recording medium 30 used for recording the TP. The TP recording control unit 12a causes the printer 20 to record TPs having different maximum ink amounts in the ink recording regions, based on the result of the determination performed by the medium determining unit 12 d.

According to the above configuration, in the recording control apparatus 10, before the printer 20 is caused to execute the recording of the TP, the type of the medium used for the recording of the TP is determined, and the ink amount range of the TP is determined based on the determined type of the medium. Therefore, it is possible to avoid causing the printer 20 to record the TP of the ink recording area including a portion of the high Duty side that is not beneficial to the correction value calculation.

Further, according to the second embodiment, the TP recording control unit 12a causes the printer 20 to record a predetermined pre-TP earlier than the recording of the TP, and the medium determining unit 12d determines the medium type of the recording medium 30 used for recording the TP based on the read value of the pre-TP thus recorded.

According to the above configuration, in the recording control apparatus 10, the printer 20 can be prevented from recording the TP including the ink recording region including a part of the high Duty side which is not useful for the correction value calculation by determining the medium type based on the read value of the pre-TP and determining the ink amount range of the TP.

The recording medium 30 on which the TP is recorded is not limited to the special paper, the plain paper, and the recycled paper described so far. Various types of recording media having different ink bleeding tendencies can be targets for recording TPs.

In the present embodiment, the case of calculating the correction value for each nozzle 23 includes not only the case of calculating the correction value so as to correspond to each of all the nozzles 23 except the target nozzle which the recording head 22 has, but also the case of calculating the correction value so as to correspond to some of the nozzles 23 except the target nozzle which the recording head 22 has.

Description of the symbols

1 … system; 10 … recording control means; 11 … a control unit; 12 … records the control program; 12a … TP recording control part; 12b … correction value calculation unit; 12c … correction recording control part; 12d … medium judging unit; a display part 13 …; 14 … operation receiving part; 15 … communication IF; 20 … printer; 21 … conveying mechanism; 22 … recording head; a 23 … nozzle; 24 … carriage; 26 … nozzle rows; 30 … recording media; 40 … color measuring device; 50. 60, 61, 62 … TP.

Claims

1. A recording control device that controls a recording device that ejects ink from a plurality of nozzles to perform recording, the recording control device comprising:

a test pattern recording control unit that causes the recording device to record a test pattern including a plurality of ink recording regions having different ink amounts;

a correction value calculation unit that calculates a correction value of the amount of ink for each of the nozzles based on a read value of the ink recording area of the test pattern to be recorded;

a correction recording control unit that causes the recording device to record an image in which the amount of ink in each of the nozzles is corrected by the correction value,

in the case where the type of the recording medium on which the test pattern is recorded is a second recording medium in which the ink is more likely to bleed than the first recording medium, the correction value calculation unit may calculate the correction value using a smaller maximum ink amount in the ink recording region corresponding to the read value than in the case where the type of the recording medium on which the test pattern is recorded is the first recording medium.

2. The recording control apparatus of claim 1,

the correction value calculation unit determines the type of medium on which the test pattern is recorded based on the read value, and determines the maximum ink amount based on the determination result.

3. The recording control apparatus of claim 1,

a medium determination unit that determines a medium type of a recording medium used for recording the test pattern,

the test pattern recording control section causes the recording device to record test patterns having different maximum ink amounts in the ink recording area, based on a result of the determination.

4. The recording control apparatus according to claim 3,

the test pattern recording control section causes the recording device to record a predetermined pre-test pattern earlier than the recording of the test pattern,

the medium determination unit performs the determination based on a read value of the pre-test pattern recorded.

5. A recording apparatus that performs recording by ejecting ink from a plurality of nozzles, the recording apparatus comprising:

a test pattern recording control section that records a test pattern including a plurality of ink recording areas having different ink amounts;

a correction recording control unit for recording an image in which the amount of ink in each of the nozzles is corrected by the correction value,

6. A recording control method for controlling a recording apparatus that performs recording by ejecting ink from a plurality of nozzles, the recording control method comprising:

a test pattern recording step of causing the recording device to record a test pattern including a plurality of ink recording regions having different ink amounts;

a correction value calculation step of calculating a correction value of the amount of ink for each nozzle based on a read value of the ink recording area of the test pattern to be recorded;

a correction recording step of causing the recording device to record an image in which the amount of ink in each of the nozzles is corrected by the correction value,

in the case where the type of the recording medium on which the test pattern is recorded is a second recording medium in which the ink is more likely to bleed than the first recording medium, the maximum ink amount in the ink recording region corresponding to the read value used in the calculation of the correction value in the correction value calculation step is smaller than in the case where the type of the recording medium on which the test pattern is recorded is the first recording medium.